1. Field of the Invention
The present invention generally relates to displays and, more particularly, the present invention relates to interactive display surfaces.
2. Background Art
Interactive computing devices, such as personal computers, mobile telephones, and personal digital assistants (PDAs), for example, play an increasingly important role in modern life. More and more, users of these devices rely on them as resources for effective time management, efficient communication, enhanced productivity, and even for entertainment. As interaction with computing devices has become an ever more frequent and important aspect of performing daily activities, the user friendliness of the input/output (I/O) interfaces enabling those interactions may prove to be a determinative factor in their practical utility.
For example, where computing devices were once typically stationary desktop or workstation based units, for which a standard QWERTY type keyboard and cathode ray tube (CRT) monitor provided adequate I/O support, today's highly mobile multi-tasking user requires a more consolidated and efficient interface. Several alternative interface options are presently available, including those enabling voice activated input, but few are more popular than the intuitive and visually appealing touch screen display. Perhaps no cognitive behavior is more instinctive than visual recognition of a desired object combined with selection of that object by means of reaching out and touching it. A touch screen display caters to this intuitive impulse by tying both output, i.e., display, and input, i.e., selection, to a common, visually compelling, symbol—typically through use of an icon or visual thumbnail.
Another aspect of touch screen displays that make them appealing and easy to interact with is their scalability. This may be apparent from the use of relatively large, wall mounted touch screen displays for delivery of educational and entertainment content at a museum, for example. In that setting, a visitor may approach the display, on which a variety of static or dynamic images may be shown, and select an image by touching its representation. As a result of that interaction, the content delivery system controlled by the touch screen may present information and/or entertainment content associated with the selected image, as well as cue the visitor regarding additional opportunities for interaction with the display. One significant advantage of presenting interactive content by means of a touch screen I/O interface is that in addition to being pleasing to use for adult visitors, its use is intuitively obvious to children, so that they are encouraged to engage useful and informative content without the obstacle of first learning a formalistic interaction protocol, such as may be required by keyboard interfaces, for example.
Despite their notable advantages as I/O interfaces, most touch screen displays in use today suffer the significant disadvantage of being single touch systems. Interaction with the surface of the display, through a user touch, is typically detected and interpreted according to changes in any of a variety of electromagnetic properties of the surface, such as changes in capacitance or inductance at or near the touch point, for example. One of the consequences of this approach to detecting and interpreting touch is that only one touch may be processed at a time. Attempts to apply multiple touches to such a display concurrently usually give rise to a number of undesirable results.
For example, multiple touches applied more or less concurrently to a single touch display may result in priority being given to one of the touches over all others, for example due to slight differences in the timing of the multiple touches, or the relative effect on the electromagnetic display properties produced by the independent touches. Under those circumstances, the touch screen controlled system may respond appropriately to one of a number of touches, but not to others applied at about the same time, creating user confusion. Alternatively, but no less undesirably, a single touch display may attempt to respond appropriately to multiple concurrent touches by interpreting them as a single touch at some geometric or other metric average corresponding to the multiple touches. Such a response can be even more frustrating and confusing for the user because the touch “detected” by the touch screen and interpreted as system input may not correspond accurately to any individual selection entered by the user, so that the system's response may seem random and arbitrary. These and other problems associated with use of a touch screen I/O interface may be exacerbated when the touch screen is implemented as an interactive floor. Here, the foot positions of numerous simultaneous users and/or other objects on the touch surface must be detected. In addition, a floor may present the need for an interactive surface area that is large (say greater than 10 feet on a side) and that is not conveniently provided by a single display. Moreover, the display must support the physical weight of multiple simultaneous users.
One approach to overcoming the described disadvantages associated with single touch, touch screen displays is shown by FIG. 1. FIG. 1 shows a diagram of a system for detecting touches to a display surface utilizing an overhead camera to record interactions between the feet of multiple users and a touch screen surface in the form of an interactive floor. System 100, in FIG. 1, includes overhead camera 104 mounted on ceiling 102, and users 110 and 120 interacting with touch screen display surface 106.
One advantage of the system shown in FIG. 1 for detecting concurrent multiple touches of display surface 106 is that it does not rely on monitoring changes to the electromagnetic properties of display surface 106 due to contact with a user. As a result, user 110 and user 120, as well as other users, may concurrently contact display surface 106, and even move about on display surface 106, without introducing intractable complexity to the detection scheme. However, the approach shown by FIG. 1 suffers from at least one significant disadvantage flowing from interposition of users 110 and 120 between display surface 106, at which touching is occurring, and overhead camera 104, through which touching is being detected.
As may be seen from FIG. 1, a consequence of the approach of system 100 is that the physical presence of users 110 and 120 between overhead camera 104 and display surface 106 can obscure the exact location of touch points 112, 114, 122, and 124. For example, shadow 116, produced by user 110, may prevent overhead camera 104 from capturing either or both of touch points 112 and 114.
Similar difficulties may obscure the precise interaction of user 120 with display surface 106 at touch points 122 and 124. Furthermore, under different circumstances, shadow 126, produced by user 120, may not obscure touch points 122 and 124 produced by user 120, but may obscure the precise location of touch points 112 and/or 114 produced by user 110. Moreover, as the number of users utilizing display surface 106 grows more numerous, and as the user interactions become more frequent and/or dynamic, the described touch detection failures are likely to proliferate.
Although it may be possible in principle to reduce the incidence of detection failure by several means, such as providing a plurality of cameras corresponding to camera 104, and/or increasing the overhead distance of camera 104, those solutions may prove to be very expensive or otherwise impracticable, depending on available resources and the type of venue in which the display surface is to be implemented. For example, in an environment in which low ceilings prevent elevation of overhead camera 104, and aesthetic considerations weigh against use of many overhead cameras, implementation of a system like system 100 may be out of the question.
Accordingly, there is a need to overcome the drawbacks and deficiencies in the art by providing a solution offering reliable and accurate touch detection of an interactive display surface.